[Form] Add option to disable 'extra fields' validation #9302
Description
Consider situation
$form = $formFactory->createNamedBuilder('', 'form', [], ['csrf_protection' => false])
->add('a', 'integer')
->setMethod('GET')
->getForm()
;
$form->handleRequest($this->getRequest());
var_dump($form->isValid());
now on example.com/test.php?a=1 form is valid. but on example.com/test.php?a=1&utm_source=zzz&... form is invalid, because there are extra fields
So i request an option, to disable extra fields validation